3D CAD drawing:
Bracket for Pentax 645 300mm ED f/4 lens

Contents:

1. Draw a bracket for the back end of lens
2. Draw a bracket for the front end of lens
3. Draw a 180 teeth pulley for motor focus of the lens
4. To be continued

Note:
I take no responsibility or liability for what are written here, you use the information at your own risk!

1, CAD draw a bracket for back end of lens:

Introduction:

I have already made a pair of tube ring holders for my guiding system. This time I make a drawing of two tube ring holders to my Pentax 645 medium format lens, the 300 mm ED f 1/4.

Pentax 645 300 mm bracket at back end:

I have started with the tube ring that is towards the camera, the back end. I choose a similar design as I had for the Tokina lens. But this lens is much heavier and I increased the dimension of it. I have the same height as I had to the Canon 300 mm lens, I want the pulley sit at the same place so I can reuse the focus motor bracket and simple just switch between the lenses. The top end I also made more compact.

The nuts is placed into pockets to not have to thread them later.

When I 3D-print it later I have tweaked the 3D-printer with spring loaded rods. You can see the details here: 3d-printer setup. Earlier I adjusted the frame of the 3D-printer.

The depth of it is 20 mm and the thickness of the ring is 7 mm, is it strong enough to hold this heavy lens ? I will know after some cold nights if it's enough.

The screw can not be too long, if, they will hit the lens body and destroy it.

The size of this screw is M6. Now I have to make another drawing to the front tube ring. The diameter of the barrel at the front is of a bigger diameter.